Industrial drilling tools



2,712,983 Patented July 12, 1955 INDUSTREAL DRILLING TOOLS Jacob llurtz, Teaneck, N. 3.

No Drawing. Original application June 1, 1949, Serial No. 96,65, new Patent No. 2,607,676, dated August 19, 1952. Divided and this application February 29, 1952, Serial No. 274,305

9 Claims. (Cl. 51-309} This invention relates to industrial tools comprising abrasive grains, such as diamonds or hard metallic abrasive and cutting materials, embedded in a metallic carbide alloy of high abrasion and shock resistance.

More particularly it relates to drill bits in which particles of diamonds or othe cutting materials such as tungsten carbide are embedded in the working face of the bit. Such drill bits have extensive adaptations in the mining and oil well drilling industries as well as in many other uses.

It is an object of this invention to provide an industrial drill bit in which the material used as matrix is hard, tough, abrasion resistant, shock resistant, easy to form, easy to weld to any suitable shank material and readily worked to permit the embedding of diamonds or any suitable cutting material in the face thereof.

Heretofore making diamond drill bits and the like was a long tedious process. The desired quality of hardnss and toughness of the matrix material was ditficult to achieve and control, and the crown containing the diamonds required an additional soldering or brazing operation to bond it to the steel shank. Frequently. due to marked diiierences in the expansion coefficients between the crown and the shank, the crown cracked and broke away from the shank, or strains would be set up in the structure to cause the crown to break away shortly after it was put into service. Likewise when using cemented carbide inserts, the inserts would crack away from the main body of the material. The main body of the material would soon wear away, or if made sufficiently hard would crack in service shortly thereafter.

Heretofore the diamonds or hard cemented carbide inserts would have to be brazed into the holder as a separate operation, and due to the marked differences of expansion between the shank and the carbide inserts,

thermal strains would develop to cause cracking away of the diamonds or cemented carbide at the time of making the braze or shortly after putting the unit to work.

The hard matrix material of the drill bit of the present invention and the method of producing it entirely eliminates the aforementioned difiiculties. Briefiy described, the hard alloy of the present invention consists essentially of refractory metal carbides, tungsten carbide for example, cobalt, nickel, manganese, copper, and a small but effective amount of beryllium combined in the proportions and according to the method described in my copending application filed June 1,1949, Serial No. 96,615, now Patent No. 2,607,676 of which this application is a division and hereinbelow:

I first provide a refractory tungsten carbide, 200 mesh or finer made by any known means. Instead of tungsten carbide, I may use any of the refractory metal carbides titanium, zirconium, vanadium, chromium, tantalum and molybdenum or suitable combinations of carbides from this groupfor example a mixture of 85% tungsten carbide and titanium carbide. A mixture of 50% tungsten carbide, molybdenum carbide, 15% titanium carbide. A mixture of 30% tungsten carbide, 30%

2 molybdenum carbide, 20% vanadium carbide, 20% titanium carbide, etc. It is to be understood that these groupings and combinations are only given by way of example, and that the invention herein is by no means limited thereto.

This finely divided metal carbide powder, or combinations of metal carbide powders, is then placed in a carbide lined or stainless steel ball mill, and to this is added 6% by weight of finely divided pure cobalt metal powder, and the two are ball milled together for a sufficiently long time to uniformly distribute the cobalt throughout the mass. This first ball milling will take from 6 to 96 hours depending of course on the original fineness of the powders used. It is essential however, to get a uniform distribution and a thorough commingling of all the ingredients. This I call refractory metal carbide Mixture A.

I next prepare a bonding, densifying, and hardening mixture, which I call Mixture B. This mixture consists of pure nickel, manganese, and copper powders, and

\ beryllium in alloy form, either as nickel-beryllium alloy,

or beryllium copper alloy. These powders are combined in a specific manner, and in a ratio in the order of 65% by Weight of nickel, 25% by weight of managnese, and 10% by weight of copper. Although the beryllium may be added as a copper beryllium alloy replacing a portion of the copper, I find it more convenient to replace a portion of the nickel by a nickel beryllium alloy powder, contining 10% beryllium, so that the amount of beryllium in the alloy mixture B is not less than 0.25% and not more than 3% by weight. The presence of the small but efiective amount of beryllium provides an alloy bonding material that can be heat treated to give a harder, tougher, and greater wear resistant body.

In preparing mixture B, l first weigh out the requisite amount of nickel powder 200 mesh and liner, and then add the required amount of the nickel beryllium alloy powder in finely divided form. The two are thoroughly mixed as by ball milling, until they are thoroughly commingled and uniformly distributed. This usually takes from 1 to 4 hours. The manganese and the copper powder, both pure and in finely divided form, are then added in amounts specified below to bring the composition of this mixture to the required value.

Grams 1. Nickel powder 3562.50 2. NiBe (10% alloy) 30.()2.5 3. Manganese powder 25.0 4. Copper 10.0

All the powders are mixed and ball milled for a further period to get a thorough distribution of all the ingredicuts.

The proportions constituting alloy mixture B give a resultant alloy containing 62.0-64.75% nickel 3.0-.25% Be 25.0% Mn The final alloy mixture is then formed by thoroughly mixing from -60% of alloy mixture A and 10-40% of alloy mixture B. Here again it is important to get a thorough mixing to assure a uniform distribution of all the ingredients. This final mixture 1 call mixture C. The final mixing may be done dry in carbide lined or stainless steel ball mills using steel or carbide balls, or it may be done Wet using carbon tetrachloride or the like. If the final ball milling is done wet, care must be exercised to continue the mixing while the carbon tetrachloride is driven oil to prevent segregation of any of the ingredients.- After thorough drying, mixture C can then be packed in air tight containers and is ready for use in making either diamond impregnated core bits, or, in combination with sintered hard metal carbide inserts, rotary type rock drilling bits, or in making any unit requiring a hard tough abrasion resistant material.

The reason for taking special care to get a uniform distribution and a thorough commingling of all the ingredients of mixture A, to thoroughly mix the ingredients of mixture B until they are thoroughly commingled and uniformly distributed, to get a thorough mixing to assure a uniform distribution of all the ingredients in preparing mixture C and to drive off all the carbon tetrachloride to prevent segregation of any of its (the mixtures) ingredients as above directed is to insure an alloy of homogeneous composition.

Whether this alloy is to be used in making diamond embedded core bits or rotary type rock drilling bits, the procedure, except for proper modification of the carbon molds and the manner of holding the abrasive grain or inserts in place, is the same. For the sake of simplicity there is described hereinbelow a method of making a diamond embedded core bit in accordance with this invention.

One form of apparatus to be used in the hot pressing of the alloy consists essentially of a high frequency or any other type of furnace with suitable range of and controls for temperature, and a hydraulic press with suitable controls for pressure, having carbon or graphite molds suitably machined to receive and hold the diamonds or cemented hard carbide inserts in place. However, the apparatus used forms no part of the present invention and may be of any conventional form and design suitable for the temperature and pressure ranges required.

The graphite mold is circular in section and is suitably machined to give an annular recess and any desired bottom contour. In the bottom of this annular recess location grooves to receive and hold the diamonds in place are drilled to proper depth to assure that in the finished drill bit the diamonds will protrude the predetermined desired distance beyond the matrix. In operation the steps are as follows. placed in the location grooves as described above. A weighed amount of alloy powder mixture C is then carefully placed in annular space, and uniformly distributed. A steel shank suitably machined, and having its bottom contour serrated, is then placed in the annular space on top of the alloy powder. The mold assembly is then placed in a high frequency furnace which is positioned on the bottom platen of a hydraulic press. Pressure is applied on top face of the shank until a value approximately 500 pounds per square inch on the pressing area of the alloy powder being pressed is reached. The high frequency current is turned on, quickly heating the mold to the requisite temperature where it is held for a period of time sufficient to allow complete densification and alloying of all the ingredients. Temperature and time will depend on the particular composition used and the size and weight of the piece being pressed. After being cooled quickly to room temperature, the shank is removed and the drill bit is now fully formed with shank thoroughly welded to the alloy matrix and the diamonds securely embedded in said matrix in the arrangement and with the amount of protrusion determined by the pattern and depth of the aforementioned location grooves.

By way of example, a 2 outside diameter x 1% inside diameter x thick ring of the alloy of this invention was hot pressed and sintered and alloyed to a steel shank of the same outside diameter and inside diameter dimensions in about 10 minutes with a high frequency furnace of 30 kw. capacity and applying an initial cold pressure of approximately 500 pounds per square inch and a maximum temperature of 1250 C. with the final pressure at maximum temperature approximately 1000 pounds per square inch. As the temperature began to rise, the pressure tended to drop due to partial sintering which began to take place. The pressure however was maintained The diamonds are carefully fairly constant throughout this pressing operation by suitable adjustment of the hydraulic press. It was found advantageous to increase the pressure as the maximum temperature was approached. This pressure was maintained on the assembly until the pressed and sintered assembly had cooled down to approximately 800 C. The pressure was then released and the assembly taken out of the furnace and allowed to cool quickly to approximate room temperature. The shank was then removed from the mold.

The matrix alloys containing 90% of mixture A and 10% of mixture B have a sintering temperature about l350 C.l500 C., whereas the alloys containing 60% mixture A and mixture B have a sintering temperature of about 1100 C.-l200 C. Temperatures and pressures used in forming the drill bit of this invention should be controlled within the limits specified to obtain a drill bit of superior qualities.

Hardness of these matrix alloys will vary depending naturally on the relative proportions of mixtures A and B used. For the 90% A10% B combination the hardness is about 72-76 Rockwell C; for the 80% A20% B, it is about 68-72; for the 70% A-30% B, it is about -64; and for the 60% A- l0% B, it is about 56-60. All values are of hardness Rockwell C. Thus in forming a drill bit in accordance with this invention, the relative proportions of mixtures A and B used are chosen to obtain the desired value of hardness for the particular use for which the drill bit is primarily designed.

For a drill bit that was extremely tough, shock and abrasion resistant, a combination that gave exceptionally good results was mixture A and 30% mixture B; mixture A contributing 65.8% by weight of metal carbides, 4.2% by weight of cobalt; and mixture B contributing 19.5% by weight of nickel plus beryllium, 7.5% by weight of manganese and 3% by weight of copper to the final alloy. The hardness of this alloy when pressed and sintered was about 60-64 Rockwell C.

Coefiicients of thermal expansion of this group of alloys are considerably higher than for the ordinary sintered carbide compositions. The values vary somewhat depending on composition. For A-10% B combination the coefiicient is approximately 8-9 10 and for the 60% A-40% B it is 1243x10 For the 70% A-30% B combination it is 12X l0" Values given are in inches per inch per C. and are approximate average values for the range 400-600 C. Because of these higher thermal expansion values, the alloys are particularly well adapted to be sintered and welded to the steel shanks ordinarily used in the mining and oil well drilling industries and other industries in which diamond and tungsten carbide studded drill bits are used because they ensure a firm weld therebetween. The use of these alloys as a crown material in making diamond studded drill bits not only eliminates cracking and breakage due to extreme thermal strain but also eliminates a separate brazing operation of the crown to the shank.

It is to be understood that where reference is made to various metal carbides, that the respective saturated form of carbide is meant.

Having thus described my invention, what I claim is:

1. As an article of manufacture, a drill bit comprising diamond particles embedded in a pressed and sintered alloy of homogeneous composition high strength and hardness, high thermal expansion and high abrasion and shock resistance comprising 90-60% by weight of a first separately prepared mixture and 10-40% by weight of a second separately prepared mixture in which said first mixture comprises 94% by weight of at least one metal carbide of the group consisting of tungsten, titanium, zirconium, vanadium, chromium, tantalum and molybdenum and 6% by weight of cobalt and said second mixture comprises 65% by weight of nickel and beryllium combined, 25% by weight of manganese and 10% by weight of copper in which the beryllium is not less than .25

nor more than 3.0% of the total of said second mixture and welded to a metallic shank.

2. As an article of manufacture, a drill bit comprising metallic carbide particles embedded in a pressed and sintered alloy of homogeneous composition high strength and hardness, high thermal expansion and high abrasion and shock resistance comprising 90-60% by weight of a first separately prepared mixture and 40% by weight of a second separately prepared mixture in which said first mixture comprises 94% by weight of at least one metal carbide of the group consisting of tungsten, titanium, zirconium, vanadium, chromium, tantalum and molybdenum and 6% by weight of cobalt and said second mixture comprises 65% by weight of nickel and beryllium combined, by weight of manganese and 10% by weight of copper in which the beryllium is not less than .25% nor more than 3.0% of the total of said second mixture and welded to a metallic shank.

3. As an article of manufacture, a drill bit comprising diamond particles embedded in a pressed and sintered alloy of homogeneous composition high strength and hardness, high thermal expansion and high abrasion and shock resistance comprising 90-60% by weight of a first separately prepared mixture and 10-40% by weight of a second separately prepared mixture in which said first mixture comprises 94% by weight of tungsten carbide and 6% by weight of cobalt and said second mixture comprises 65% by Weight of nickel and beryllium combined, 25% by weight of manganese and 10% by Weight of copper in which the beryllium is not less than .25 nor more than 3.0% of the total of said second mixture and welded to a metallic shank.

4. As an article of manufacture, a drill bit comprising metallic carbide particles embedded in a pressed and sintered alloy of homogeneous composition high strength and hardness, high thermal expansion and high abrasion and shock resistance comprising 90-60% by Weight of a first separately prepared mixture and 10-40% by weight of a second separately prepared mixture in which said first mixture comprises 94% by weight of tungsten carbide and 6% by weight of cobalt and said second mixture comprises 65% by weight of nickel and beryllium combined, 25% by weight of manganese and 10% by weight of copper in which the beryllium is not less than .25% nor more than 3.0% of the total of said second mixture and welded to a metallic shank.

5. As an article of manufacture, a drill bit comprising diamond particles embedded in a pressed and sintered alloy of homogeneous composition high strength and hardness, high thermal expansion and high abrasion and shock resistance consisting of 70% by weight of a first separately prepared mixture and by weight of a second separately prepared mixture in which said first mixture comprises 94% by weight of tungsten carbide and 6% by weight of cobalt and said second mixture comprises 65% by weight of a nickel and beryllium alloy, 25% by weight of manganese and 10% by weight of copper in which said nickel beryllium alloy contains beryllium in an amount not less than .25% nor more than 3.0%

of the total of said second mixture and welded to a metallic shank.

6. As an article of manufacture, a drill bit comprising metallic carbide particles embedded in a pressed and sintered alloy of homogeneous composition high strength and hardness, high thermal expansion and high abrasion and shock resistance consisting of by weight of a first separately prepared mixture and 30% by weight of a second separately prepared mixture in which said first mixture comprises 94% by Weight of tungsten carbide and 6% by weight of cobalt and said second mixture comprises 65% by weight of a nickel and beryllium alloy, 25% by weight of manganese and 10% by weight of copper in which said nickel beryllium alloy contains beryllium in an amount not less than .25% nor more than 3.0% of the total of said second mixture and welded to a metallic shank.

7. As an article of manufacture, a drill bit comprising hard sharp cutting particles comprising one of the materials from the group consisting of diamonds and metallic carbides embedded in a pressed and sintered alloy of homogeneous composition, high strength and hardness, high thermal expansion and high abrasion and shock resistance comprising -60% by weight of a first separately prepared mixture and 10-40% by Weight of a second separately prepared mixture in which said first mixture comprises 94% by weight of at least one metal carbide of the group consisting of tungsten, titanium, zirconium, vanadium, chromium, tantalum and molybdenum and 6% by weight of cobalt and said mixture comprises 65 by weight of nickel and beryllium combined, 25 by weight of manganese and 10% by weight of copper in which the beryllium is not less than .25 nor more than 3.0% of the total of said second mixture and welded to a metallic shank.

8. As an article of manufacture, a drill bit comprising hard sharp cutting particles comprising one of the materials from the group consisting of diamonds and metallic carbides embedded in a pressed and sintered alloy of homogeneous composition, high strength and hardness, high thermal expansion and high abrasion and shock resistance comprising 90-60% by weight of a first separately prepared mixture and 10-40% by weight of a second separately prepared mixture in which said first mixture comprises 94% by weight of tungsten carbide and 6% by weight of cobalt and said second mixture comprises 65 by weight of nickel and beryllium combined, 25 by weight of manganese and 10% by weight of copper in which the beryllium is not less than .25 nor more than 3.0% of the total of said second mixture and welded to a metallic shank.

References Cited in the file of this patent UNITED STATES PATENTS 2,410,512 Lindquist et al Nov. 5, 1946 2,582,231 Catallo Jan. 15, 1952 2,607,676 Kurtz Aug. 19, 1952 2,630,383 Swartz Mar. 3, 1953 

7. AS AN ARTICLE OF MANUFACTURE, A DRILL BIT COMPRISING HARD SHARP CUTTING PARTICLES COMPRISING ONE OF THE MATERIALS FROM THE GROUP CONSISTING OF DIAMONDS AND METALLIC CARBIDES EMBEDDED IN A PRESSED AND SINTERED ALLOY OF HOMOGANEOUS COMPOSITION, HIGH STRENGTH AND HARDNESS, HIGH THERMAL EXPANSION AND HIGH ABRASION AND SHOCK RESISTANCE COMPRISING 90-60% BY WEIGHT OF A FIRST SEPARATELY PREPARAED MIXTURE AND 10-40% BY WEIGHT OF A SECOND SEPARATELY PREPARED MIXTURE IN WHICH SAID FIRST MIXTURE COMPRISES 94% BY WEIGHT OF AT LEAST ONE METAL CARBIDE OF THE GROUP CONSISTING OF TUNGSTEN, TITANIUM, ZIRCONIUM, VANADIUM, CHROMIUM, TANTALUM AND MOLYBDENUM AND 6% BY WEIGHT OF COBALT AND SAID MIXTURE COMPRISES 65% BY WEIGHT OF NICKEL AND BERYLLIUM COMBINED, 25% BY WEIGHT OF MANGANESE AND 10% BY WEIGHT OF COPPER IN WHICH THE BERYLLIUM IS NOT LESS THAN .25% NOR MORE THAN 3.0% OF THE TOTAL OF SAID SECOND MIXTURE AND WELDED TO A METALLIC SHANK. 